Electron-discharge device



Jan. 29, 1929. 1,700,472

" E. M. DELORAINE ELECTRON DISCHARGE DEVICE Filed May 19, 1925 Patented Jan. 29, 1929.

UNHTEDSTATES PATENT: orifice.-

EDMOND M. DELOBAINE, F BLACKHEATH, LONDON, ENGLAND, ASSIGNOR TO' 'WES T ERIN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

nnncrnou-mscnanen nnvrcn Applicationfiled May 19,1925. Serial No. 31,267, and in Great Britain Kovember,3,'1924.

This invention relates to electron discharge devices and more particularly to such-devices capable of operating at high voltages.

In such devices, one electrode is heated to produce a stream pf electrons which are impelled at high velocity toward the other electrode by virtue of a difference of potential between them. It is well known that the effect of the electronic bombardment on an electrode is '10 to increase the temperature of the latter, the

kinetic energy of the electron flow being converted into heat. The temperature of a bombarded electrode rises until the rate at which energy is transferred to it by the bombardus ing electrons becomes equal to the rate at which it is dissi ated from it.

In electron discharge devices at present in.

use, no advantage is taken of the heating up of the anode. on the contrary, means are 2 often provided for dissipating this heat and keeping the temperature of the anode comparatively low. The heat thus withdrawn from the anode represents a loss of energy and is merely carried away by radiating or cooling means.

The present invention aims to utilize the energy ordinarily dissipated on the anode by employing it to produce a thermionic emission to be used eificiently in the further operation 39 of the device. It is known that in the case of the medium sized electron discharge devices of the ordinary type, the power dissipated on the anode is of the same magnitude as the power used to heat the cathode and may be much greater in the case of the larger power tubes at present in operation.- It is clear that if instead of being wasted it were employed forresupplying the cathode with heat energy, a large economy of filament current would be the result and "for the continued functioning of the device an external source of energy might even be eliminated.

According-to one embodiment of theinvention, this object is achieved by constructing the electron discharge device in such a way that when used in connection with a suitable circuit, theelectrodes reverse their, functions of anode and cathode, respectively, at short intervals. This is accomplished by supplying alternating current tothe respective electrodes so that during one half cycle of the current, one electrode is charged with a high positive potential with respect to the other electrode, and an electron stream is caused to flow from the electrode at low potential to theelectrode at higher potential. Upon the reiversal of current from the alternating source, the polarity of the electrode is reversed. This arrangement utilizes the heat energy dissi- 'formed into any desirable shape, whereby a sufficiently largesurface area' is obtalned. A plurality of control electrodes or grids 13 and 14 are located between the electrodes 11 and 12. These electrodes may be supported within the vessel-10 in any desirable manner and a suitable leads are brought throughthe vessel for connection to any desired circuit. To connect the device in an oscillation circuit, the electrodes 11 and 12 ac connected together throu h a tuned circuiticomprising two arms 15, an 16 ohm inductance and a condenser 17. Preferably only one connection is made to each electrode, while the remaining ends are the anode best short circuited for reasons to be hereinafter described. The control electrode 13 is connected in the oscillation circuit through a feed back winding 18 of the inductance. A suitable resistance connected in the grid circuit keeps the power dissipated on the grid sufficiently low and serves to impress on the control electrode a negative potential with. respect to the electrode 11. A condenser 20 is connected across the resistance 19 to provide a conductive path for discharges to the grid 13. A similar circuit connects the control I electrode 14 with the timed circuit by means of feed back coupling 21,resistance 22 and condenser 23. A power transformer 24, having the highside thereof connected to the inner ends of the inductances 15 and 16 and the low side connected to any, suitable alternating current source supplies high voltage current to the electrodes 11 and 12. A by-pass condenser 25 of suitable capacity is connected across the high winding of transformer 24 and in series with the inductances 15 andlt. This condenser is designed to offer lowimedanceto the high frequency currents and a. 'ghimpedance to low frequency currents.

When starting, the electrodes 11 and 12 may be heated to incandescence by any suitable means, the object being to heat the electrodes so that electronic emission can take place. For example, this may be carried out by heating the electrodes 11 and 12 with a high frequency coil 26 surrounding the vessel-10. Current supplied to this coil will induce current in the-electrodes 11 nd 12, acting as secondaries of the high ,freliuency transformer 26, whereby they will be heated to a temperature high enoiigh to emit electrons. The high frequency coil is only necessary to initially heat the electrodes to incandescence, since the alternating current applied to the electrodes through transformer 24'and inductances 15 and 16. continually keeps the electrodes in an active state so that on each half cycle of the alternating current, when one of the electrodes positively charged with respect to the other" electrode, the second electrode is an electron emitter. Upon a reversal of the current, the electrodes change their function so that the electrode performing as a cathode now becomes an anode and the former anode is now a cathode or electron emitter.

Referring to the operation of the device as an oscillator, it will be seen that when the electrode 11is heated, the grid perform' ing its function in the well-known manner.

and a high positive potential applied'to the electrode 12, the system will oscillate as the controlling action of the grid 13 is stronger than the action of the grid 14. The electrode 12 (which is now the anode) is at a high temperature, which will be further increased by the bombardment of electrons from the electrode 11 (which is the cathode); When the circuit is reversed due to the alternating potential from the power source, the electrode 12 2' "which is at a high temperature, will emit electrons and oscillations will occur in away absolutely similar to that described previously, since the electrode 11, (whichis now the anode) will be charged with. a high positive potential. It will be seen that one active electrode will be the cathode with respect to the other electrode, and upon reversal of whereby an electron flow passes between saidelectrodes, and a pair of grids between said electrodes, each of said grids alternately controlling said electron fiow.

2. In combination, an electron discharge device comprising two electron emitting electrodes, means for heating saidelectrodes to incandescence, alternating current applied to each of said electrodes whereby an electron flow passes between said electrodes, and a pair of grids between said, electrodes, each of said grids alternately controlling said electron flow when the nearest electrode is functioning as the cathode. Y

3. In combination, an electron discharge device having two electron emitting electrodes and two grids, means for 'initially heating said electrodes, an output impedance for the amplified waves connected between said electrodes, a pair of input circuits connected between said grids and said'electrodes.

respectively, means for periodically reversing the potential of said electrodes to correspondingly. reverse the function of said electrodes as cathode and anode.

In witness whereof, I hereunto subscribe my name this 18th day of May, A. D. 1925. EDMOND M. DELORAINE. 

